Inside pipe cutter



J. BUCKLES Sept. 20, 1938.

Filed Sept. 26,

Patented Sept. 20, 1938 INSIDE PIPE CUTTER James Buckles,

Goose Creek, Tex.

Application September 26, 1935, Serial No. 42,171

3 Claims.

'Ihis invention relates to an inside pipe cutter.

An object of the invention is to provide a pipe cutter shaped to beinserted into a pipe, stuck in a well bore, and adapted to cut byrotation.

Another object of the invention is to provide a pipe cutter comprising acutter body having outwardly movable blades mounted therein normallyheld in retracted position in combination with a mandrel movable axiallythrough the body arranged to engage and move the blades outwardly whilethe device is being rotated in the pipe to be cut.

Another objectA is to provide a cutter of the character describedwherein the mandrel is normally held in inactive position by a yieldablespring or seat with means thereon for the application of liquid underpressure thereto to actuate the mandrel into Contact with the blades tomove the blades outwardly into cutting relation with the pipe to be cut.

A further feature resides in the provision of a pipe cutter of thecharacter described wherein the mandrel constitutes also a weightsuspended from, and having a swiveling connection with, a wire linewhereby the mandrel'may be lowered into position to actuate the bladesoutwardly into pipe-cutting position, or elevated.

With the above and other objects in view the invention has particularrelation to certain novel features of construction, operation andarrangement of parts, examples of which are given in this specicationand illustrated in the accompanying drawings, wherein:

Fig. 1 shows a vertical sectional view oi the 35 cutter.

Fig. 2 shows a cross-sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 shows a cross-sectional view taken on the line 3-3 of Fig. 1.

Fig. 4 shows a vertical sectional view of another form of the cutter,showing the blades in inactive position, and

Fig. 5 shows a fragmentary side view, partly in section, of the form ofcutter shown in Fig. 4, with the blades in active position.

Referring now more particularly to the drawings wherein like numerals ofreference designate similar parts in each of the figures, the numeral Idesignates a tubular cutter body vadapted to be connected to the lowerend of a tubular operating string 2 whereby the cutter may be rotatedfrom the ground surface.

At its lower end the cutter body is provided with the verticallyelongated tubular slots 3 in which the cutter blades 4 work. The bladesare (o1. lei- 0.8)

pivoted at their upper ends on the cross-pins 5 and their lower ends areprovided with the outwardly directed bits 6. The blades are normallyheld retracted by the llat springs l whose upper ends are fastened tothe body and whose lower ends press against the outer sides of theblades as shown in Figs. 4 and 5. Any desired number of blades may beemployed, three, the preferable number, being shown.

Axially movable in the body l there is a mandrel 8 and surrounding thismandrel there is a strong coil spring 9 whose lower end is seated on theinside shoulder I0 of the body and whose upper end resists against thenut I I threaded on the upper end of the mandrel. This nut may beadjusted to regulate the tension on the spring 9.

The upper end of the body is formed with the cylinder I2 and on theupper end of the mandrel, fitting closely within this cylinder, there isa piston I3.

The mandrel 8 has an axial channel I4 therethrough from end to end. Theinner sides of the blades 4, beneath the pins 5, are provided with thedownwardly converging bearing faces I5, and the lower end of the mandrelB is tapered to engage said faces and force the lower ends of the bladesoutwardly upon downward movement of the mandrel.

In operation the cutter is lowered into the well bore and into the pipeI6 stuck therein. Liquid under pressure is then forced down through thestem 2 and against the piston I3 and the mandrel 8 will thereby beforced downwardly and will gradually move the blades 4 outwardly,carrying the bits 6 into contact with the pipe to be cut. Meanwhile,suiiicient liquid will pass through the channel I4 to flush the bits andto keep them cool during the cutting operation. When the pipe I6 issevered, the liquid pressure may be released and a spring 9 willwithdraw the mandrel upwardly allowing the springs 'I to retract theblades and the tool may then be withdrawn fromv the pipe.

In actual practice a spear is usually carried by the operating string 2so that when the cutting is completed, the cutting tool may be loweredand the spear engaged with the cut-01T section and said section removedwith the cutter, or the cutter may be withdrawn from the well, and apipe puller lowered into engagement with the cut-ofi section, and saidsection removed preparatory to making another cut.

In the form shown in Figs. 4 and 5, the mandrel 8a is in the form of anelongated weight adapted to be let down through the cutter body I tocirculate down to the bits iorilushing them and keeping them cool. f v

In other respects the form shown in Fig. 4 is the same as that shown inFig. 1.

The drawings and description disclose what is now considered to bepreferred forms of the invention by way of illustration only, while thebroad principle of the invention will be defined by the appended claims.

VWhat I claim is:

1. A pipe cutter adapted to cut by rotation and comprising a tubularcutter body having an inside shoulder, outwardly movable blades whoseupper ends are pivoted to the body and whose lower ends are swingableoutwardly and formed With outwardly directed bits, said blades havingdownwardly converging inside faces, means normally holding the bladesretracted into inactive position, a mandrel movable axially in the bodyhaving an adjustable stop thereon, a coil spring on the shoulder andacting against the stop and normally holding the mandrel elevated intoinactive position, a piston on the mandrel above the stop and fitted inthe body, a tubular operating string to the lower end oi which the bodyis attached and through which liquid under pressure may be forcedagainst the piston to move the mandrel downwardly against said faces toforce the blades outwardly.

2. A pipe cutter adapted to out by rotation and comprising a tubularbody whose upper end is formed into a cylinder, said cylinder having aninside annular shoulderat its lower end, outwardly movable blades whoseupperY ends are pivoted to the body and whose lower ends are swingableoutwardly and formed with outwardly directed bits, the blades havingdownwardly converging, inside faces, means normally holding the bladesretracted into inactive position, a mandrel movable axially in the bodyand extended into the cylinder, an annular inside shoulder in the bodyspaced beneath the lower end of the cylinder, a coiled spring resting onsaid last mentioned shoulder and supporting the mandrel and normallyholding it elevated into inactive position, means on the mandrel forregulating the compression of said spring, a piston on the mandrelfitted within the cylinder and whose downward movement is limited by thefirst mentioned shoulder at the lower end of the cylinder, the lower endof the mandrel being positioned to operate against said faces to forcethe blades outwardly upon downward movement of the mandrel.

3. A pipe cutter adapted to cut by rotation and comprising a tubularbody whose upper end is formed into a cylinder, outwardly movable bladeswhose upper ends are pivoted to the body and whose lower ends areswingable outwardly and formed with outwardly directed bits, the bladeshaving downwardly converging, inside faces, means normally holding theblades retracted into inactive position, a mandrel movable axially inthe body and extended into the cylinder, said mandrel being tapered atits lower end to engage the converging inside faces of the blades, ashoulder in the lower end of the body, a coil spring resting on the saidshoulder, and supporting the mandrel and holdingthe mandrel normally ininactive position, threads on the upper end of the mandrel adapted toreceive a nut for holding said coil spring adjustably in place, a pistonin the cylinder above said coil spring, an internal annular shoulder atthe lower end of said cylinder vfor restricting the downward movement ofthe piston, the upper end of the mandrel being reduced and externallythreaded, a nut threaded onto said reduced end of the mandrel forlocking the piston in place and a tubular operating string above thepiston for the passage of fluid under pressure to operate the mandreldownwardly.

JAMES BUCKLES.

